Recently, more and more friendly user interfaces and products using the same are invented. For example, augmented reality (AR) or mixed reality (MR) is integrated into a wearable display, such that the interaction between the user and the machine can be friendlier and the user experiment is enhanced.
Vision calibration is required for the wearable display to solve the matching conflict of an eye perception and a displaying content. Particularly, a wearable display or a head mounted display integrated with a depth sensor to sense the location or the movement of hands or fingers. If the vision perception and the display content cannot be matched up, the display content is not easy to use. Eye location and seeing angle to the wearable display or the head mounted display are always predefined. If the eye location is shifted then the display cannot detect this situation and cannot take any action immediately.